The invention relates to a lifting device, in particular, a lifting platform for motor vehicles, comprising at least one extendable lifting column that is comprised of a tubular jacket and a lifting cylinder unit arranged at least partially therein and whose upper end supports a load receptacle.
In practice, such lifting platforms are comprised of one or several telescoping lifting columns having at their upper free ends a load receptacle configured in the form of a running rail or in a different way. The lifting columns can be extended by means of lifting cylinder units that are arranged in a tubular jacket, respectively. The tubular jacket serves in this connection for receiving and compensating differential moments, for example, bending moments, resulting from non-uniform load distribution that are introduced through the load receptacle. The pressure forces, on the other hand, are applied or received by the lifting cylinder units. Moreover, the tubular jacket is provided for protecting the lifting cylinder units.
For various labor tasks to be performed on the motor vehicles to be lifted, it is advantageous to provide in the upper end area of the lifting column a compressed air connector so that required compressed air, for example, for pneumatic screwdrivers or for cleaning components can be tapped directly in the vicinity of the working position. In this way, long compressed air hoses that always present a tripping hazard are no longer required in the workshop.
In DE 200 12 375 a lifting platform is disclosed that comprises an energy supply connector, for example, for compressed air, on running rails or load receptacles. In the lifting platform described therein, a conduit element, for example, for compressed air, extends through the tubular jacket. The farther this lifting platform and thus also the conduit element is removed from the connected compressor, the more frequent problems occur, when, for example, impact wrenches require instantaneously a lot of compressed air for detaching seized wheel nuts, which compressed air, however, is not available in sufficient quantity with such a conduit configuration. Moreover, the conduits that extends to the consumer often have a small cross-section because of the minimal mounting space that is available, and this leads to additional losses.